A conventional lighting system includes a ballast, and a fluorescent tube that is removably coupled to the ballast. When receiving an alternating current input voltage, the ballast starts the fluorescent tube and limits a current flowing through the fluorescent tube. If one who wishes to use a light emitting diode (LED) tube that is relatively energy saving in the conventional lighting system merely replaces the fluorescent tube with the LED tube such that an LED driver of the LED tube is coupled to the ballast, the LED driver would be damaged due to the operation of the ballast. In order to prevent damaging the LED driver, the ballast must be removed or bypassed before the installation of the LED tube, such that the LED driver is not coupled to the ballast after the installation.